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authorIngo Molnar <mingo@kernel.org>2017-06-20 12:06:46 +0200
committerIngo Molnar <mingo@kernel.org>2017-06-20 12:19:14 +0200
commit2055da97389a605c8a00d163d40903afbe413921 (patch)
tree6aec7243076aab2d4d239f03e34598752ce1512a /kernel/sched
parent5822a454d6d22297c5fcd66264120587b2ec21cd (diff)
sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming
So I've noticed a number of instances where it was not obvious from the code whether ->task_list was for a wait-queue head or a wait-queue entry. Furthermore, there's a number of wait-queue users where the lists are not for 'tasks' but other entities (poll tables, etc.), in which case the 'task_list' name is actively confusing. To clear this all up, name the wait-queue head and entry list structure fields unambiguously: struct wait_queue_head::task_list => ::head struct wait_queue_entry::task_list => ::entry For example, this code: rqw->wait.task_list.next != &wait->task_list ... is was pretty unclear (to me) what it's doing, while now it's written this way: rqw->wait.head.next != &wait->entry ... which makes it pretty clear that we are iterating a list until we see the head. Other examples are: list_for_each_entry_safe(pos, next, &x->task_list, task_list) { list_for_each_entry(wq, &fence->wait.task_list, task_list) { ... where it's unclear (to me) what we are iterating, and during review it's hard to tell whether it's trying to walk a wait-queue entry (which would be a bug), while now it's written as: list_for_each_entry_safe(pos, next, &x->head, entry) { list_for_each_entry(wq, &fence->wait.head, entry) { Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/wait.c24
-rw-r--r--kernel/sched/wait_bit.c4
2 files changed, 14 insertions, 14 deletions
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 6bcd7c3c4501..17f11c6b0a9f 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -16,7 +16,7 @@ void __init_waitqueue_head(struct wait_queue_head *wq_head, const char *name, st
{
spin_lock_init(&wq_head->lock);
lockdep_set_class_and_name(&wq_head->lock, key, name);
- INIT_LIST_HEAD(&wq_head->task_list);
+ INIT_LIST_HEAD(&wq_head->head);
}
EXPORT_SYMBOL(__init_waitqueue_head);
@@ -68,7 +68,7 @@ static void __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
{
wait_queue_entry_t *curr, *next;
- list_for_each_entry_safe(curr, next, &wq_head->task_list, task_list) {
+ list_for_each_entry_safe(curr, next, &wq_head->head, entry) {
unsigned flags = curr->flags;
if (curr->func(curr, mode, wake_flags, key) &&
@@ -176,7 +176,7 @@ prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_ent
wq_entry->flags &= ~WQ_FLAG_EXCLUSIVE;
spin_lock_irqsave(&wq_head->lock, flags);
- if (list_empty(&wq_entry->task_list))
+ if (list_empty(&wq_entry->entry))
__add_wait_queue(wq_head, wq_entry);
set_current_state(state);
spin_unlock_irqrestore(&wq_head->lock, flags);
@@ -190,7 +190,7 @@ prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_ent
wq_entry->flags |= WQ_FLAG_EXCLUSIVE;
spin_lock_irqsave(&wq_head->lock, flags);
- if (list_empty(&wq_entry->task_list))
+ if (list_empty(&wq_entry->entry))
__add_wait_queue_entry_tail(wq_head, wq_entry);
set_current_state(state);
spin_unlock_irqrestore(&wq_head->lock, flags);
@@ -202,7 +202,7 @@ void init_wait_entry(struct wait_queue_entry *wq_entry, int flags)
wq_entry->flags = flags;
wq_entry->private = current;
wq_entry->func = autoremove_wake_function;
- INIT_LIST_HEAD(&wq_entry->task_list);
+ INIT_LIST_HEAD(&wq_entry->entry);
}
EXPORT_SYMBOL(init_wait_entry);
@@ -225,10 +225,10 @@ long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_en
* can't see us, it should wake up another exclusive waiter if
* we fail.
*/
- list_del_init(&wq_entry->task_list);
+ list_del_init(&wq_entry->entry);
ret = -ERESTARTSYS;
} else {
- if (list_empty(&wq_entry->task_list)) {
+ if (list_empty(&wq_entry->entry)) {
if (wq_entry->flags & WQ_FLAG_EXCLUSIVE)
__add_wait_queue_entry_tail(wq_head, wq_entry);
else
@@ -251,7 +251,7 @@ EXPORT_SYMBOL(prepare_to_wait_event);
*/
int do_wait_intr(wait_queue_head_t *wq, wait_queue_entry_t *wait)
{
- if (likely(list_empty(&wait->task_list)))
+ if (likely(list_empty(&wait->entry)))
__add_wait_queue_entry_tail(wq, wait);
set_current_state(TASK_INTERRUPTIBLE);
@@ -267,7 +267,7 @@ EXPORT_SYMBOL(do_wait_intr);
int do_wait_intr_irq(wait_queue_head_t *wq, wait_queue_entry_t *wait)
{
- if (likely(list_empty(&wait->task_list)))
+ if (likely(list_empty(&wait->entry)))
__add_wait_queue_entry_tail(wq, wait);
set_current_state(TASK_INTERRUPTIBLE);
@@ -308,9 +308,9 @@ void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_en
* have _one_ other CPU that looks at or modifies
* the list).
*/
- if (!list_empty_careful(&wq_entry->task_list)) {
+ if (!list_empty_careful(&wq_entry->entry)) {
spin_lock_irqsave(&wq_head->lock, flags);
- list_del_init(&wq_entry->task_list);
+ list_del_init(&wq_entry->entry);
spin_unlock_irqrestore(&wq_head->lock, flags);
}
}
@@ -321,7 +321,7 @@ int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, i
int ret = default_wake_function(wq_entry, mode, sync, key);
if (ret)
- list_del_init(&wq_entry->task_list);
+ list_del_init(&wq_entry->entry);
return ret;
}
EXPORT_SYMBOL(autoremove_wake_function);
diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
index c891b34e1896..f8159698aa4d 100644
--- a/kernel/sched/wait_bit.c
+++ b/kernel/sched/wait_bit.c
@@ -205,8 +205,8 @@ int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_en
.wq_entry = { \
.private = current, \
.func = wake_atomic_t_function, \
- .task_list = \
- LIST_HEAD_INIT((name).wq_entry.task_list), \
+ .entry = \
+ LIST_HEAD_INIT((name).wq_entry.entry), \
}, \
}